Diagnostic Imaging in Acute Cardiopulmonary Disease

Value of chest sonography in the diagnosis and management of acute chest disease

PURPOSE

The aim of this study was to investigate the value of chest sonography in the diagnosis and management of patients with chest radiograph opacities in an emergency department.

METHODS

Seventy-eight patients with acute chest complaints whose chest radiographs showed opacities underwent chest sonography. The initial diagnosis (based on clinical manifestations and the chest radiograph), the sonographic diagnosis (before any invasive procedures), and the final diagnosis were compared. The impact of chest sonography on the management of patients with chest opacities was also analyzed.

RESULTS

The initial diagnosis was in concordance with the final diagnosis in 60 (77%) of the 78 patients, while the sonographic diagnosis was in concordance with the final diagnosis in 75 (96%) of the patients. Chest sonography therefore significantly increased the rate of correct diagnoses from 77% (95% confidence interval, 67-87%) to 96% (95% confidence interval, 92-100%; p < 0.0001). Sonography provided new information in 52 patients (67%): a different diagnosis from the initial diagnosis in 18 patients and additional diagnostic information in 34 patients. New information gained from sonography affected the management of 35 patients. Sonography also provided help in guiding 42 (70%) of 60 invasive diagnostic procedures and 22 (73%) of 30 invasive therapeutic procedures for which chest radiography and physical examination had failed to or were unsuitable to provide guidance. Overall, sonography assisted in the management of 64 (82%) of 78 patients. Sonography was of no benefit in 14 patients (18%).

CONCLUSIONS

We conclude that chest sonography can complement chest radiography and is of value in the diagnosis and management of emergency department patients with acute chest diseases presenting as opacities on chest radiographs.

Computed tomography in established adult respiratory distress syndrome. Correlation with lung injury score

STUDY OBJECTIVES

To identify serial changes in the appearances of the lungs on computed tomography (CT) in patients with established adult respiratory distress syndrome (ARDS). Second, to evaluate any relationship between the extent of morphologic abnormalities on CT anatomic and physiologic derangement using a numeric score of the severity of lung injury.

DESIGN

Retrospective, descriptive.

SETTING

Adult intensive care unit, Department of Radiology, and outpatient department of a national tertiary referral center.

PATIENTS

Eight patients meeting diagnostic criteria for ARDS able to tolerate CT scanning during the acute phase of their illness and who survived to be reevaluated during convalescence.

INTERVENTIONS

Mechanical ventilatory support. Conventional intensive care support of other failed systems a appropriate.

MEASUREMENTS AND RESULTS

Thin-section CT scans of the lungs categorized as to extent (calculated percent volume of abnormal lung), distribution, and dominant disease pattern. Concurrent lung injury score (LIS) was recorded at the time of the CT during the acute phase of illness (mean, 26 days; range, 3 to 48 days after precipitating event) and at follow-up (96; 17 to 187 days). On initial CT scans, disease patterns included ground-glass opacification (8/8), parenchymal distortion (8/8), multifocal areas of consolidation (6/8), reticular opacities (6/8), and linear opacities (5/8). On follow-up scans, there was clearing of consolidation in all patients, but ground-glass opacification persisted in four of eight patients. The reticular pattern persisted unchanged in five of eight patients, became more extensive in two of eight, and developed in one. A reticular pattern was most pronounced in areas that had been densely consolidated previously. Evidence of parenchymal distortion, present on the initial scan in all patients, persisted in six of eight patients. Computed tomographic features suggestive of emphysema developed in one patient. The LIS revealed moderate to severe ARDS in all patients initially; this decreased to a mild or zero LIS at follow-up. Overall, there was 76.9% +/- 5.3% abnormal lung on the initial CT scan and 34.5 +/- 9.3% on the follow-up CT scan. There was a significant correlation between the extent of abnormalities on CT and LIS (r = 0.75, p < 0.01).

CONCLUSIONS

The CT appearances of patients with ARDS who survive are variable and relate to the pattern of disease in the acute phase. Furthermore, the extent of CT abnormalities correlates strongly with LIS in both the acute phase and at follow-up.

The radiologic diagnosis of autopsy-proven ventilator-associated pneumonia

An abnormal chest roentgenogram is essential for the diagnosis of ventilator-associated pneumonia. The diagnostic accuracy of various roentgenographic signs of pneumonia has not been assessed previously in the portable anteroposterior roentgenograms obtained in ventilated patients. Seven roentgenographic signs (air bronchograms, alveolar infiltrates, silhouette sign, cavities, fissure abutment, atelectasis, and asymmetric infiltrates superimposed on diffuse bilateral infiltrates) were evaluated for their accuracy in predicting pneumonia alone, in combination with other signs, or in combination with clinical parameters. The last roentgenogram prior to autopsy of 69 ventilated patients was interpreted by three reviewers and the above signs were correlated with autopsy evidence of pneumonia. Pneumonia was present in 24 (35 percent) of the 69 autopsies. No roentgenographic sign had a diagnostic efficiency of greater than 68 percent. By stepwise logistic regression, the presence of air bronchograms was the only roentgenographic sign that correlated with pneumonia in the total group, correctly predicting 64 percent of pneumonias. In patients without adult respiratory distress syndrome (ARDS), the presence of air bronchograms or alveolar infiltrates correlated with pneumonia, while in patients with ARDS, no roentgenographic sign and only the clinical parameter of purulent sputum correlated with pneumonia. Only a minority (7/22) of worsening alveolar infiltrates in all groups were due to pneumonia and were often confused with ARDS. Alveolar hemorrhage occurred with a surprising frequency (38 percent of autopsies), including 13/45 (29 percent) patients without pneumonia. Alveolar hemorrhage was associated with 29 percent of multiple air bronchograms and 30 percent of bilateral alveolar infiltrates in patients without pneumonia. We conclude that in intubated patients with diffuse bilateral roentgenographic infiltrates, no roentgenographic sign correlates well with pneumonia. No clinical parameter added to the accuracy of either an alveolar infiltrate or an air bronchogram in patients without diffuse infiltrates. Pulmonary hemorrhage and/or infarction are frequent autopsy findings in intubated patients and may be confused radiologically with pneumonia.